Paper wasps are 3/4 to 1 inch long, are reddish -brown with a yellow circle,  and have longer legs and slenderer bodies than yellow jackets and hornets. Their abdomen taper at both ends. Paper wasps are sometimes called "umbrella wasps" because their nests consist of a single exposed comb suspended by a narrow stalk. There are 22 species of paper wasps in North America and approximately 700 species world-wide. 

FOOD SOURCES
Adults forage for nectar, their source of energy, and for caterpillars to feed the larvae (young). They are natural enemies of many garden insect pests, so are considered to be beneficial insects. 

NEST
Paper wasps build clusters of hexagonal paper cells. Mixing masticated (chewed) wood pulp with adhesive saliva, these paper nest cells act as larval nesting chambers for the young wasps. (The Chinese inventor of paper was legend to have been inspired by observing these wasps chewing bark.) Other wasps of the Vespid family, are potters, building their nests from mud and saliva. Similar to other social wasps, paper wasps abandon their nests in the autumn, with the mated queens overwintering. A queen killed in the fall or early spring will eliminate an entire nest during the summer. 

HABITAT
Paper wasps may be more inclined to build nests in attics than yellow jackets or hornets because their nests lack an outer covering. They will build a nest anywhere in the Central Valley during the dry months. They can usually be found in outdoor rest rooms, dense bushy habitats, and even on fences.

Larvae are at all stages of development in an active wasp nest. 

Above, you can see larva that have not yet covered their individual cells.
Below, a juvenile wasp peeks out from his cell cap and then emerges.

STINGS, TREATMENT AND CONTROL
Paper wasps are considered beneficial insects due to their predation on non-beneficial garden pests. Unfortunately, wasps will defend their nest if disturbed and sting repeatedly. After being stung, apply a poultice of a meat tenderizer to the wound. If the sting is not deep, this will break down the components of the sting fluid, reducing pain. If you experience difficultly in breathing after being stung, you are having an allergic reation and should seek emergency medical treatment immediately.

Individual paper wasps and their nests can be sprayed with an aerosol insecticide (or even hairspray or a cleaning fluid). It is best to knock down the nest if possible after spraying all the wasps on it. Do not position yourself below the nest after spraying it, the wasps will fall and sting you. After spraying the nest stand to one side, after all have fallen, step on them.
images - I. Lindsey

Other types of Vespid wasps:
Yellow Jackets (meat bees)
Mud Daubers